The radioactive capsule, in the palm of my hand, appeared surprisingly small, seemingly ordinary. By then, I’d memorized the various numbers, the guard rails of my radioactive quarantine. No conversations closer than four feet. No riding public transportation for four days. No sleeping beside my husband for at least five. And the strictest of all: no contact with my 3 1/2-year-old son for at least a week. The bulleted warnings filled the sheet of paper I was handed. The goal: to radiate my thyroid literally to death.

 

  I had been diagnosed 10 months before, after weeks of living in denial. As a medical reporter, I knew my symptoms likely weren’t benign: perpetual anxiety, shaking hands, sudden weight loss, a racing pulse. What were the possibilities? Chronic panic attacks? An impending heart attack? Not particularly upbeat options at age 37.

 

  Then one night in the shower, I recalled that my mother developed hyperthyroidism in her mid-forties. The tiny butterfly-shaped gland, located in the neck, drives the body’s metabolism, influencing everything from sleep to weight loss to heart rhythms. When the thyroid becomes “hyper,” it pumps out too much hormone. The condition, diagnosed with a simple blood test, tends to run in families.

 

  Holding that slim hope in my hand, I called my family physician. A few minutes into the appointment, I was lying on the exam table, EKG leads attached to my chest. My pulse was 140 beats a minute.

 

  When my physician called with the results, I was ridiculously relieved. I was hyperthyroid, but it was fixable. Well, sort of.

 

  In the hope of avoiding radiation, I started taking a medication, Propylthiouracil (PTU), to inhibit the thyroid’s excess production and possibly put the symptoms into remission. But the medication carried a rare but potentially life-threatening side effect, called agranulocytosis, in which the body’s white cells and ability to fight infections are drastically reduced. The long-term option, radioactive iodine, also came with a catch. I couldn’t get pregnant for six months and ideally 12, an eternity for a woman passing her thirty-eighth birthday. Nor was that route guaranteed. In 20% of cases, for reasons unknown, the radioactive iodine doesn’t work.

 

  I’d love to describe a flash of epiphany, a moment when my scrambled brain (a jumpy thyroid can wreak havoc on concentration) and racing heart settled on a decision. But clarity, I realized as the months scrolled by, can be ephemeral. All I knew is that I couldn’t handle perpetual limbo. When I raised a margarita to mark my fortieth birthday, pregnant or not, I didn’t want to still be circling the same set of indecisions.

 

  So we developed our radiation plan. My husband and son would drive five hours to visit family for a few days. When they returned, I would vanish from my own house, leaving before my son returned from preschool and sneaking back to spend the nights in the little efficiency apartment located behind our home. For seven days, mommy was taking “a work trip,” I told my son. I hugged them both a long time before they drove off.

 

  Soon after, I left for the hospital. I had already packed the refrigerator with my favorite foods. A stack of DVDs sat on the television, new books beside the bed.

 

  The hospital clinician walked me back to a small room, not much larger than a walk-in closet, with boxes stacked along the walls. She gave me a quick rundown. Eat off disposable dishes. Flush the toilet twice after each use.

 

  Then she bent over and opened a lead-lined suitcase on the floor. From within, she pulled a lead-lined cylinder, a bit smaller than a coffee can, setting it on the counter beside her. Using a pair of tweezers, she extricated the oblong capsule and gingerly deposited it in my hand.

 

I must have given her a long look. She laughed, a sharp sound: “These protections are more for us than for you.”

 

  I nodded, washing the pill down, ignoring my instincts: “Don’t swallow—toxins ahead!”

 

  Driving home, my skin felt prickly and flushed, clearly radioactive. I took a deep breath, talking myself down. The radioactive iodine, as it’s pulled into the thyroid, wasn’t supposed to cause any discomfort, other than the sense of being untouchable and inescapably alone.

 

  Within six months, I would know if the treatment had worked. Six months passed, and then 12, my thyroid stubbornly holding on despite the radioactive assault. Then its activity began to drop. Shortly after my fortieth birthday, I learned that my skittish thyroid had finally shrunk until it was minimally active. To replace the missing hormone, I started taking Synthroid, a synthetic replacement.

 

  Finally I inhabited my own body again, rather than one perpetually revved on adrenalin. But that sense of relief was mixed with sadness and lingering anger that a tiny gland could essentially derail my fertility, running out the clock on my last few fertile years, my best shot at creating another life ultimately overshadowed by the desire to reclaim my own.